Process for making artificial wool imitation filaments and artificial wool filaments



y 1946- HElNZ-HORST E. VON K. zu KORNL-IGG 43? NOW BY JUDICIAL CHANGE 0F NAME H. VON KOHORN PROCESS FOR MAKING ARTIFICIAL WOOL IMITATION FILAMENTS AND ARTIFICIAL WOOL FILAMENTS Filed Feb. .25, 1939 2 Sheets-Sheet 1 WHEEL THREAD GUIDES SPINNERE? ATTORNEY$ july 9, 1946. v 2,403,437 HElNZ-HORST E. VON K. ZU KORNEGG NOW BY JUDICIAL CHANGE OF NAME H. VON KOHORN PROCESS FOR MAKING ARTIFICIAL WOOL IMITATION FILAMENTS AND ARTIFICIAL WOOL FILAMENTS Filed Feb. 25-, 1939 2 Sheets-Sheet 2 INVENTOR.

14 FOP/VIEW" Patented July 9, 1946 PROCESS FOR MAKING ARTIFICIAL WOOL IMITATION FILAMENTS AND ARTIFICIAL WOOL FILAMENTS Heinz-Horst E. Von Kohorn Zu Kornegg, New York, N. Y., now by judicial change oi name Henry Von Kohorn, assignor, by mesne assignments, to Asher Blum, New York, N. Y.

Application February 25, 1939, Serial No. 258,498

15 Claims.

This invention relate to the manufacture of filaments, threads, yarns, ribbons, staple, or similar fibres and the products made therefrom, having the characteristics of natural wool in respect to appearance, feel, serimetric and physical properties. I produce such wool imitation filaments, etc., from cellulose containing vegetable sources according to the viscose method.

It is known that a temporary wool character can be obtained when producing filaments from viscose by spinning the viscose at a ripeness greatly deviating from the customary-one. But

nary ripeness conditions are not permanent and disappear during the subsequent treatment of the filaments and/or their fabrics such as boiling, ironing, etc.

When hereinafter referring to ripeness degrees, the so-called Hottenroth-ripeness is meant, which is determined according to the following method: 20 grams of viscose are diluted and mixed with 30 com. of water. Then a 10% ammonium chloride (NH4C1) solution is slowly added until the viscose reaches the coagulation point. The number of cubic centimeters of NHlCl solution necessary to reach this coagulation point is the ripeness or ripenes degree of the viscose.

In the drawings:

Fig. 1 is a diagrammatic view of the stretching portion of a spinning machine upon which the improved filaments are spun and stretched.

Fig. 2 is a cross-sectional view of the improved filaments produced by the invention.

Fig. 3 is a side view of a portion of theme.- ments showing the fissures or cracks occurring along the lengths of the said filaments.

Fig. 4 is a cross-sectional view of the improved filaments made by the invention and having somewhat different cross-section characteristics than that of the filaments shown in Fig. 2.

Fig. 5 is a diagrammatic view showing the floating, the drying and the opening apparatus preferably employed for the manufacture of the improved staple fibers.

The viscosity referred to hereinafter is determined according to the ball-fall method, carried out-gin the following manner: The viscose under examination is poured into a vertical glass tube of 300 mm. length and 25 mm. diameter.

mm. column of viscose between the upper and the lower mark, is measured. The number oi seconds required by the steel ball to drop said 200 mm., is the viscosity of the viscose.

such. wool characteristics produced by extraordi- When spinning ordinary viscose rayon or I staple fibre, the viscose is spun at a usual ripe= ness of ,7 to 13 and a viscosity of to 50. tap

proximately the same figures are meant when referring hereinafter to ordinary or usual ripeness and "ordinary or usual viscosity.

According to my invention, I obtain filaments, etc., with permanent wool characteristics by preparing a viscose of high viscosity and by spinning this viscose into a bath containing a comparatively large quantity of certain salts. A salt content of {i% zinc sulphate or more, besides the normal sodium sulphate content, was found very satisfactory for this purpose. But under certain circumstances aluminum sulphate, magnesium sulphate, ammonium sulphate, nickel sulphate and cobalt sulphate were also found suitable. It is also possible to use a combinetion of twoor more of the above described salts, always over and above the normal sodium sul- 25 phate content. The reason I provide for these salts in my spinning bath is, that these salts not only improve the wool-like feel of the filaments produced according to this process, but I also find, that the presence of these salts at 3 the given high percentages counteract the drawbacks of spinning a highly viscous viscose. On the other hand, the high viscosity of the viscose counteracts the objectionable. efiects of the high percentage of zinc and other sulphates men tioned in the spinning bath, which occur, when using such high percentages in spinning a viscose of normal viscosity. 1

When referring in this specificationto thehigh salt conten a salt content of 4% zinc sulphat or more, over and above the normal sodium sulphate content of about 23%, or a combination of any two or more of the above mentioned -salts, and having a similar efiect as 4% or more zinc sulphate, is meant. The above mentioned "similar efi'ect is intended to refer to the wool characteristics of the filaments only.

As mentioned above, various attempts have been made to produce wool-like filaments by spinning a viscose with abnormal ripeness, both 7 Very high and very low. It is, however, known to people skilled in the art that it is very dimcult t control the ripeness of viscose in either a very fresh (unripened) or in a very ripe condition. I' have discovered the new and desirable effect of spinning a viscose with a high viscosity a period from 10 to 24 hours.

acce tor a 3 but at normal ripeness into a spinning bath containing a high percentage of zinc or similarly acting sulphates, in order to obtain filaments, etc., with a wool characteristic.

with a very high viscosity into a normal spinning I have alsodiscovered that the disadvantage of spinning a viscose bath, and the disadvantages of spinning a vis= cose of normal viscosity into a spinning bath containing a high percentage of zinc sulphate, can be avoided by spinning viscose with a high'viscosity into a spinning bath containing a high percentage of zinc or similarly acting sulphates.

- In this specification the term spinning viscosity line crumbs at a temperature of 22 degrees C.

The shredded alkali cellulose is then immediately sulphidized with 33% carbonbisulphide at a temperature of 22 to 25 degrees C. for about 90 min- The xanthate obtained is dissolved in a dilute caustic soda solution, so as to form a vis- During this time the viscosity drops to about 850 and the ripeness to 12.6. (According to the old method, viscose is stored for about 90 hours.) The viscose is then spun (projected through splnnerets) into a spinning bath containing 11% sulphuric acid, 23% sodium sulphate and 4% zinc sulphate at a temperature or 45 degrees C.

The filaments obtained are either collected in one oi the' known devices and then washed.

bleached, etc., in order to finish them or they can be finished in one continuous operation whilst continuously running.

Example 2.,Mode ofoperation as in Example 1 with the diflerence that between the shredding and xanthating operations, the alkali cela lulose is stored away or kept in suitable containers for a period of up to 10 hours. I Example 3.--Mode of operation as in Example 1 with the diflerence that between the shredding and sulphidizing step the alkali cellulose is stored away or kept in suitable containers for Example 4.-Mcde of operation as in Example 1 with the difference that between the shredding and sulphidlzing step the alkali cellulose is stored away or kept in suitable containers for a period from 24 to 40 hours.

Example 5.Mode of operation as in Examples 1 to 4 with the difference that the shredding is carried out at a temperature between 20 and 30 degrees C.

Example 6.--Mode of operation as in Examples 1 to with the difference that, before spinning, the viscose is stored up to 12 hours.

Example 7.--Mode of operation as in Examples usual concentration at a temperature of over 22 degrees 0., which has an ageing eflect on the cellulose. The exact concentration oi! the caustic soda. solution, the time and the temperature at which the cellulose is steeped in this solution depend upon the type of cellulose used and the "degree of ageing desired.

Some examples of carrying out my process are described in my earlier application Serial No. 191,420, filed February 19, 1938. If the cellulose isto be aged at all, it is obvious that by ageing it during the steeping operation considerable cose containing 7% alkali arid 7% alpha-cellulose, and is stored in tanks. At this point the viscose has a viscosity of 900 and a ripeness of 13.

The viscose is then illtrated and evacuated im- 1 'mediately, within about 6 hours.

ing effect as in Example 4.

space and time can be saved as against the ordinary method of ageing cellulose after the shredding in separate containers; using a caustic soda solution of 18% concentration and a steeping time of about one hour, about the following temperatures would have to be used in order to obtain the same degree of ageing as described in same age- (d) 22 to 36 degrees C. to obtain ing effect as in Example 5.

In order to keep a constant temperature of the caustic soda solution during the process of mercerizing, I can circulate this solution through the mercerizing vessel either by means of a pump or automatically by the thermo-syphon principle. This latter arrangement consists oi a tank provided with a heating coil and situated underneath the mercerizing vessel. It is connected with this vessel by means of a feed pipe and a return pipe. The caustic soda solution contained in the circulation tank is heated and rises through the feed pipe into the mercerlzing vessel on account of its lighter specific weight due to its higher temperature. The feed pipe is connected with the mercerizing vessel at its lowest point., The hot caustic soda solution rises through the mercerizing vessel and the cellulose. There is an overflow provided at the top of this vessel connected with the return pipe and the circulating tank located below. Thus, the comparatively cool caustic solution returns to the circulation or heating tank in order -to be reheated.

This arrangement provides for an automatic heat exchange without necessitating pumps or other mechanical devices. A constant temperature of predetermined degree may be kept by means of a resistance thermometer or thermostats, which in turn operate electric valves regulatlng the heat supply in the circulating" tank.

All of the examples given in this specification for making viscose will result in a viscose having a spinning viscosity of over 500 as claimed in this specification. 'I'here'are, of course, many combinations and variations possible and I decellulose with a caustic soda solution or the it throughspinneretsinto a s n b nthe same age- I solve the xanthate obtained into viscose and store said viscose for 24 hours at a temperature of 18 degrees C. to give the viscose a viscosity of 750.

I then spin this viscose into filaments according to the methods described.

Example 9.-Viscose prepared according to Examples 1 to 8 is spun into filaments on a spinning machine provided with the following dewhich the filaments take up to one complete turn. From here, the thread passes on to and around the second glass wheel which is-driven at a peripherical speed greater than that of the first wheel. The number of turns taken by the filaments around this second wheel depends on the position of the eventual collecting device. The filaments may be taken up by (a) Bobbins, reels or any other winding-up mechanism,

(b) Pots or buckets,

(c)' Rollers or other guiding or feeding devices on which the filaments, whilst continuously running, are subjected to washing and bleaching or that feed the filaments .to a cutting device.

The immersion length of the filaments in the spinning bath, the position of the glass wheels and the angles in the direction of the filaments or threads formed by these wheels must be determined according to the desired results and will vary with the typesof viscose (Examples 1-8) and spinning bath (Example 13) used.

Example 10.--Mode of operation as in Example 9 with the diflerence that there may be thread guides provided between the spinneret and the first glass wheel, between the first glass wheel and the second and between the second glass wheel and the take-up arrangement, in order to increase the tension and stretch on the filaments.

Example 11.-Mode of operation as in Example 9 with the difference that one of the glass wheels is omitted and that tension is applied to the filaments between the remaining glass wheel and the spinneret or the take-up arrangement. There may be additional thread guides Provided.

and explained in Examples 9-12'may be used.

After the viscose squirted through the spinneret has partly been precipitated so as to form tubes which still contain fluid viscoseon the inside, they are given tension only sumcient to withdraw the filaments but not stretching them immediately after their formation.

After the filaments-have thus been given time to take the required shape, they are stretched sufliciently by various methods to obtain 'sufilcient strength. This can be done by thread guides, rollers, wheels, etc., as described in Examples 9-12.

The composition of the viscose and of the spinning bath cause the filaments produced to have a rough or cracked surface, similar to the scales of natural wool. Furthermore, the filaments twist in such a manner as to have a cross sectionsimilar to a horse shoe, the ends of which touch or overlap, as illustrated in Fig. 2 and Fig. i.

I have found that filaments, etc., obtain good wool-like qualities by spinning viscose as described under the following conditions:

I spin (project through a spinneret) viscose into a spinning bath of the composition as outlined. The distance between the spinneret and the (first) drawing-off mechanism is between lb and 30 inches, all of which, or a portion. of which may be the actual immersionlength in the spinning bath,

There may be one or two drawing-oil mechanisms provided anterior to the eventual collected device. According to the present invention, I

withdraw the filaments formed from the spinneret under as little tension as possible so that the initial formation of the filaments which consists of the formation of a cellulose tube, which is comparatively rigid, but which still contains fluid viscose on the inside.) takes place in loose condition. After the filaments have thus been formed, under conditions which allow them to assume the required shape and structure caused by the efiects of the viscose and the spinning bath upon each other, I apply tension or stretch the filaments by increasing the drawing-off speed.

This increase in the drawing-off speed is such as to cause a cracking or breaking of the rigid outer cellulose layerof the filaments formed, which is Example 12.--Mode of operation is in Example amples, it has been found advisable to coagulate these filaments in'loose condition and to apply the necessary tension after the filaments have been formed but while they still partly are in a plastic condition.

To this end and as one embodiment of my invention, a spinning device as shown on Fig. l

ments thus formed eventually, improves their wool feel and under proper conditions even re sembles the scales of the natural wool fibre. Another consequence of this method of spinning is that the filaments take the shape of a horse-shoe (Fi 2), the two ends of which almost touch or sometimes overlap, the filaments thus having an air-enclosing space in the center which increases the insulationpower and thus the warmth oi. the filaments or yarn, fabrics, etc, made fron them.

" In order to above described manner, it is important that the coagulation of the ViSCOSe and the complete regeneration of the cellulose does not take place too quickly. It is known to persons skilled in the art that Zinc sulphate retards the complete regeneration of the cellulose by quickly forming be able to treat the filaments in the surface, and a hollow, air-enclosing space or canal in the center, as shown in Figs. 2, 3, and 4.

According to my invention, I apply to the filaments such a tension by conducting them around above mentioned thread guides or guide rollers placed at various distances and angles, so as to give the final filaments the same elongation as that of the natural wool fibres they are intended to be blended with, or which they are to replace.

By regulating the composition of the spinning bath, especially in regard to' the quantity of sulphuric acid, I apply the required degree of hardness or softness to the fibres necessary in order to imitate the natural wool fibre, especially in regard to their behavior when spun into yarn.

By increasing the quantity of sulphuric acid, it

is, for instance, possible to increase the hardness of the fibres obtained up to the degree of hardness which certain kinds of wool, as for instance cross-bred, have.

It is impossible to indicate ever condition so according to my method with wool or to use them necessary in order to obtain the desired properties of thefilaments, threads, ribbons,etc., produced and it is to be understood that experiments cannot be avoided to find the most suitable con-' ditions for each particular cellulose used or the type of wool imitation fiber, etc., to be imitated. There are a great many different types of wool ranging from Merino, which has a very soft feel, to a cross-bred, which is rather hard to the touch.

When using or referring in this specification 40 .to the term filaments, this term is meant to include other viscose products, such as threads, ribbons, fibers and the like.

- 8 old method, the viscose prepared by my method changes its ripeness during the course of 2 hours, only about 0.1 to 0.15 degree.

It is known that fluctuations in the ripeness of viscose are the cause for uneven dyeing ofv the filaments or the fabric eventually produced. Ordinary viscose changes its ripeness during the two hour period, during which the contents of one spinning tank are being used up (which may form the thread of one continuous skein of rayon) by about 0.4 degree. While this fluctuation often causes uneven dyeing, the change in ripeness of 'the'viscose prepared according to my invention of about 0.15 degree is negligible.

When producing filaments, etc., according to above described methods, the filaments have a subdued lustre, which may range from a slight to a very distinct dullness. This property'is very desirable in view of the fact that natural wool is also dull and that artificial filaments produced by this method can be blended with wool or used in the place of wool without changing the appearance of the product at all, compared with a 100% woolen product.

This dullness which in contrast to other delustering methods is obtained without the use of chemical additions or mechanical treatments, is

permanent and will not be removed by any subsequent treatment of the product.

As it is intended to blend filaments produced instead of wool, these filaments should therefore resemble natural wool as closely as possible. For this purpose, the fibers, filaments, etc., produced are intentionally given the same physical properties as those of the, woolen fibres they are to be blended with or they are to replace. Such mechanical and'physical properties, of course, depend on and vary with the different-kinds of natural wool, and include staple length, crosssection, crimp, surface character, elasticity, in-

terfibre friction, color, luster, heat conductivity,

feel and appearance.

Sodium sulphate Zinc Gram per met sulphate sulphate Aluminum Nickel sulphate Cobalt Magnesium Ammonium sulphate sulphate sulphate Type of wool obtained crossbred.

l5 am fuliy aware that neither a high zinc sulphateeontent in the spinning bath nor an abnormal viscosity of the viscose, nor a stretching of the filaments after formation are essentially on new in themselves, but this invention concerns itself with their use and importance in the manufacture of wool imitation filaments, etc., and the new and desirable effect when used in combination.

Eaiamp le 13 .-Viscose prepared according to Examples 1 to 8 and spun under conditions and on .the devices according to Examples 9 to 11, is

precipitated in a spinning bath having one of the following compositions:

The dyeing properties of fibres or filaments obtained in the above described ways are excellent and of great uniformity. The reason is that the viscose prepared by my method has a very slow ripening tendency.

- ness of the artificial fibres.

In distinct contrast to the 78 It is obvious that when spinning a yarn which ,is to resemble wool, the percentage of artificial fibres used in this blended yarn can correspondingly be increased with an increasing wool-likea artificial fibre yarn can be spun, which has all the mechanical and physical properties of a pure woolen yarn. After spinning filaments according to one of the, above described methods, the filaments can either be (in the case of cut staple fibres) (a) Washed, cut and then dried; (b) Washed, dried andflthen cut; (0) Cut, washed and then dried. Without limiting myself to the below described method, I prefer to continuously wash, cut, and

A suitable method and apparatus for carrying out my process are dethen dry the filaments.

scribed in United States Patent No. 2,134,160.

In some cases, even The term washing is meant to include such treatments as de-sulphurizing, bleaching, etc.

In order to give the filaments the same or better crimp than that of the natural wool fibre, which is very desirable to the spinner whenspinning such-cut filaments into yarn, I dry and treat the filaments as follows:

Prior to drying, I open the cut filaments as well as possible by floating them in a large volume of a suitable solution and/or mechanically by passing them through one of the known wet openers. I do this because it is known that a larger part of the crimp in artificial filaments appears during the drying operation and in order A sirable for the purpose. I therefore have designed and arranged the apparatus shown in Fig. 5.

The dryer is divided into two independent units or sections 3 and 4, each of which can be worked at different speeds, temperatures, humidities, etc.

' Intermediatethese two sections, there is provided a second opener 2. The filaments passing through the first'section 3 of the dryer lose part of their moisture content and then pass through the second opener 2. The filaments which are now only in semi-wet condition are opened much more readily and are not as ougged together as when opened in wet condition. This second opener 2 can also perform a much more thorough opening operation because the action on the filaments does not have to be as gentle as when opening completely wet fibers. It is known that viscose fibers are weaker in wet condition than in dry condition and.while the first opener i is to be designed in such a way as to avoid damage by stretching or tearing of the filaments, the second opener 2 may have a much more severe action.

Thefibres having passed through said second opener 2, enter the second section 4 of the dryer in loose and fiuify condition and are capable of receiving a curl or crimp in the second section of the dryer. Anterior the first opening apparatus I is the usual spraying device 5.

By this method it is also possible to dry the filaments in the first section 3 of the dryer at a much higher temperatiure because the filaments still have a high moisture content. In the second section 4 of the dryer the temperature is correspondingly lower.

While it has been suggested to comb fibers during the drying operation in order to simplify the carding operation, I believe that I have discovered the new and desirable eflect of an opening Operation of semi-dry fibers on the crimp of the finished fibers.

The various wool-like properties of the fibers are important both from the standpoint of the spinner and the eventual consumer. The following properties, for instance, affect the making, 1. e., the spinning of the yarn rather than the wearing or use of the fabric: staple length, crosssection, crimp, surface character and inter-fiber fri i in, all of which have a direct bearing on the spinnability and the cost of the yarn spun. On the other hand, color, lustre, heat conductivity, feel and appearance are properties of importance to the consumer rather than to the producer.

One very important factor, equally important to both, is the elasticity, as this property affects the spinning as well as the wearing qualities of the fibres to a very large extent.

It its known that the spinning properties of fibres depend, to a large extent, on the surface structure (smoothness or roughness) of these fibres. It has always been considered a disadvantage of ordinary cut rayon staples that their surface was too smooth and did not result in the same good spinnability as that of cotton or of wool. As described above, I therefore, regulate the degree of roughness I apply to the filaments spun according to my process, by giving them a more or less cracked and rough surface, 'comparable to that of wool.

Through my process I am also able to give these artificial wool imitation filaments the same warmth (insulating power) as that of wool. I accomplish this by giving the filaments the described twisted shape resultingin the air-enclosing canal running in longitudinal direction through the whole length of the filaments.

wool yarn and staple fibre yarn or of a doubled woolen yarn and continuous filament rayon yarn.

In each case the cut fibres, the staple fibre yarn and the continuous filament yarn have been given the above described wool characteristics.

I claim:

1. Process for the manufacture of artificial wool imitation filaments and the like, comprising making alkali-cellulose, ageing said alkali-cellulose for not more than 20 hours at a temperature below 17 degrees C., xanthating and dissolving said alkali-cellulose into viscose, storing said viscose at a temperature of less than 19 degrees C., for less than 30 hours, to give the viscose an ordinary ripeness, and a viscosity of at least 500 and spinning said viscose into a bath containing about 11% sulphuric acid, about 22% sodium sulphide, and at least 4% zinc sulphate to form filaments.

2. Process for the manufacture of delustered artificial wool imitation filaments and the like, comprising making alkali-cellulose, sulphidizing said alkali-cellulose without ageing to form xanthate', dissolving said xanthate into viscose, storing said viscose at a temperature of less than 19 degrees C. for less than 30 hours, to give the viscose an ordinary ripeness and a viscosity of at least 500, and spinning said viscose into a bath containing about 11% sulphuric acid. about 23% sodium sulphate and at least 4% zinc sulphate to form filaments.

3. In the manufacture of artificial wool imitation filaments, making viscose with a viscosity of at least 500 and projecting said viscose through a spinneret into a spinning bathcontaining grams per liter sulphuric acid, 285 grams per liter sodium sulphate, 50 grams per liter zinc sulphate to form filaments.

4. Method for spinning artificial wool imitation filaments and the like, which comprises projecting viscose with a viscosity of at least 500 into an acid spinning bath containing at least 4% zinc sulphate and approximately 23% sodium sulphate, withdrawing the filaments under as little tension as possible and then applyi g stretch 12 1 a tation'fllaments, the steps making viscose with a viscosity of at least 500, quickly forming a membrane around the viscose streams projected acid spinning bath containing at least 4%zinc sulphate and approximately 23% sodium-sulphate, withdrawing the filaments formed under as little tension aspossible by means oi a wheel, and then applying stretch to the filaments by withdrawing them at a greater speed by means of a second wheel having a higher peripherical speed and thus causing the surface of the nnments to become roughand cracked.

6. A method for the production of artificial wool imitation filaments and the like, comprise ing projecting viscose with aviscosity of at least 500 into an acid spinning bath containing at least 4% zinc sulphate and approximately 28% sodium-sulphate, withdrawing the filaments under as little tension as possibie by means 0! a first godet wheel and then applying stretch to through a spinneret by'precipitating said viscose into an acid spinning bath containing more than 4%- zinc sulphate and approximately 23% so* chum-sulphate to form filaments, and stretching said filaments to cause said membranes to burst in circumferential .direction of the filaments to impart to the filaments a rough surface.

, 11. An artificial filament having a transverse cross-section of substantially horse-shoe shape and transverse fissures occurring along the length oi said filament obtained by projecting-viscose into a spinning bath, containing 9 to 12% suiphuric acid, to sodium sulphate and ap -proximately 4% zinc sulphate, withdrawing the said filaments, resulting in said cross-section and the filament by means of a second godet wheel having a greater periphericalspeed than'thefirst Wheel. y l

.7'. 'lhe method or producing filaments with a rough'suriace which comprises projecting viscose with a viscosity or atleast lioqthrough a spinneret'and for a certain tlmeinto a bath containing sulphuric acid, sodium sulphate and at least 4% zinc sulphate, drawing oil under as, little tension as possible the filaments formed 'so' as to allow' a comparatively rigid cellulose-tube to form on the outside of the filaments and astoailow the filaments to assume a horse-shoe shape caused .by the zinc sulphate present and then filaments formed and then applying tension to fissures, said filament because of said fissures and the shape oi said cross-section having a roughness approaching that of natural wool and havin a surface friction coefiicient the same as natural wool. a

12. As a new product, artificial woolimitation filaments and the like with a rough surface, oi

the type as obtained by coagulating viscose with a viscosity of at least 500 in an acid spinning bath containing at least 4%'-zinc sulphate over and above'the normal sodium sulphate contentoi 13. Method tor spinning artificial wool imitation "filaments and the like, which comprises projectstretching the filaments'containing coagulated' viscose but non-regenerated plastic cellulose on inside, so as to cause. said cellulose tubes formed-on the outside of the filaments to crack and thus to form a rough surface.

. 8. A process for the manufacture of artificial wool imitation filaments comprising mercerising, pressing and shredding cellulose, storing said celluloee for not more than 12 hours at a temperaing viscose with a viscosity of at least. 500 into an acid bath containing at least 4% zinc sulphate over and above the normal sodium sulphate content of 20 ,to 25%, withdrawing the filaments under as little tension as possible and then applying stretch to the filaments in order to give them a rough surface.

14. A process for the manufacture of artificial wool imitation filaments comprising mercerislng,

, pressingand shredding cellulose, storing said celture of not more thania degrees 0., sulphidizing said cellulose without ageing it to form xanthate.

dissolving said xanthate to viscose, filtrating and evacuating said viscose, andspinning said vis cose at a viscosity of at least500 into an and spinning bath containing at least 4% zincsul phate and approximately 23% sodium-sulphate to form filaments, withdrawing-said filaments under as little tension as possible by means of.

if wheel. and then applyingstretch to the ments by means oi -a second wheel having a greater peripherical speed than thefirst wheel.

, a. Inthe manuiactureoi viscose for making artificial wool imitation filaments, the steps. oi treating cellulose in a caustic soda solution, at a lulose at a temperature of not more than 18 degrees C., sulphidizing said cellulose without useing it to form xanthate, dissolving said xanthate to viscose, filtrating and evacuating said viscose,

and spinning said viscose at a viscosity of at least into an acid spinning bath containing-at least 4% zinc sulphate over and above the normal sodium sulphate content of 20 to 25% to form filaments, withdrawing said filaments under as little tension as possible by means oi a wheel,

and then applying stretch to the filaments by -means'oi a second wheel having. a greater periphoral-speed than the first wheel.

, 15. In the manufacture of viscose for making artificial wool imitation filaments, the'steps of treating cellulose in a caustic soda solution,

temperature above 22-degrees C., shredding said aged alkali-cellulose, sulphidi'zing said cellulose without to form xanthate, dissolviing said xanthate into a viscose; spinning said viscose at a viscosity of not less than 500 into an acid spinninglbath containing at least 4% zinc sulphate and approximately 23% sodium-sulphate to iormfilaments, withdrawing these filaiinents under as little tension as possible by means 01 a wheel and then applying-stretch to the filashredding said aged alkali-cellulose, sulphidizing said cellulose without further ageing to form xanthate, dissolving said xanthate into a viscose, spinning saidviscose at a viscosity of not less' than 500 into an acid spinning bath containing at least 4% zinc sulphate over and above the normal sodium sulphate content of 20 to 25% to form filaments, withdrawing these filaments under as little tension as possible by means of a ments by means of a second wheel having a reater Deripherical speed than the first wheel. 10. In the manufacture)! artificial wool imiwheel and then applying stretch to the filaments by means of a second wheel having a greater peripheral speed than the first wheel.

- HEINz-HORST E.

VON KOHORN ZU KORNEGG. 

